From 3abbb0dcb5a527fa22f40d31d0ed5737d4dda101 Mon Sep 17 00:00:00 2001
From: hyenias <58673227+hyenias@users.noreply.github.com>
Date: Sat, 20 Mar 2021 12:07:30 -0400
Subject: [PATCH] Overlapping buffers in hist_word (#234)

While experimenting with #233, a memory segmentation fault occurred.
A search of other emacs issues found a potential matching issue as
described in https://github.com/att/ast/pull/791. Also, a duplicate
PR of https://github.com/att/ast/pull/1489 was submitted. This
commit backports that fix.

src/cmd/ksh93/edit/history.c: hist_word():
- Switch from using strcpy to memmove as the two strings could overlap.
---
 src/cmd/ksh93/edit/history.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/cmd/ksh93/edit/history.c b/src/cmd/ksh93/edit/history.c
index 191f3469c..7d50ee072 100644
--- a/src/cmd/ksh93/edit/history.c
+++ b/src/cmd/ksh93/edit/history.c
@@ -1115,7 +1115,8 @@ char *hist_word(char *string,int size,int word)
 	}
 	*cp = 0;
 	if(s1 != string)
-		strcpy(string,s1);
+		/* We can't use strcpy() because the two buffers may overlap. */
+		memmove(string,s1,strlen(s1)+1);
 	return(string);
 }